static UnaryExpression PropertyValueCastToObject(ParameterExpression obj, MemberInfo propOrField)
{
Expression value = Expression.PropertyOrField(obj, propOrField.Name);
var type = Types.PropertyOrFieldType(propOrField);
if (type.IsEnum || Types.IsNullableEnum(type))
{
value = Expression.Convert(value, typeof(int));
}
return(Expression.Convert(value, typeof(object)));
}
static Action <DbCommand, object> CreateAddParametersAction(Type type)
{
var obj = Expression.Parameter(typeof(object), "obj");
var parameters = Expression.Parameter(type, "parameters");
var cmd = Expression.Parameter(typeof(DbCommand), "cmd");
var dataParam = Expression.Parameter(typeof(DbParameter), "dataParam");
var lines = new List <Expression>
{
Expression.Assign(parameters, Expression.Convert(obj, type))
};
var createParameter = typeof(DbCommand).GetMethod("CreateParameter", Type.EmptyTypes);
foreach (var prop in Types.ReadablePublicFieldsAndProperties(type))
{
var fieldOrProperty = Types.PropertyOrFieldType(prop);
if (!IsSupportedType(fieldOrProperty))
{
continue;
}
lines.Add(Expression.Assign(dataParam, Expression.Call(cmd, createParameter)));
lines.Add(Expression.Assign(Expression.Property(dataParam, "ParameterName"), Expression.Constant("@" + prop.Name)));
if (Types.IsStructured(fieldOrProperty))
{
if (fieldOrProperty != typeof(SqlTable))
{
throw new NotSupportedException($"Parameter {dataParam.Name} implements {nameof(IEnumerable<SqlDataRecord>)} but type name is unknown. Please wrap parameter by calling {nameof(Extensions.WithTypeName)}");
}
lines.Add(Expression.IfThen(
Expression.Not(Expression.TypeIs(cmd, typeof(DbCommand))),
Expression.Throw(Expression.New(typeof(NotSupportedException).GetConstructor(new[] { typeof(string) }), Expression.Constant("Structured parameters are supported only for SqlCommand")))
));
lines.Add(Expression.Assign(Expression.Property(Expression.Convert(dataParam, typeof(SqlParameter)), "SqlDbType"), Expression.Constant(SqlDbType.Structured)));
lines.Add(Expression.Assign(Expression.Property(Expression.Convert(dataParam, typeof(SqlParameter)), "TypeName"), Expression.Property(Expression.Property(parameters, prop.Name), "TypeName")));
}
else if (fieldOrProperty.IsEnum || Types.IsNullableEnum(fieldOrProperty))
{
lines.Add(Expression.Assign(Expression.Property(dataParam, "DbType"), Expression.Constant(DbType.Int32)));
}
else
{
lines.Add(Expression.Assign(Expression.Property(dataParam, "DbType"), Expression.Constant(Types.TypeToDbType[fieldOrProperty])));
}
if (fieldOrProperty == typeof(SqlTable))
{
// check if records is null
var tt = Expression.PropertyOrField(parameters, prop.Name);
var records = Expression.Property(Expression.Convert(tt, typeof(SqlTable)), "Records");
lines.Add(
Expression.Assign(Expression.Property(dataParam, "Value"), Expression.Convert(records, typeof(object))
//Expression.Condition(
// Expression.Equal(records, Expression.Constant(null)),
// Expression.Convert(Expression.Field(null, typeof(DBNull), "Value"), typeof(object)),
// Expression.Convert(records, typeof(object))
//)
)
);
}
else if (Types.CanBeNull(fieldOrProperty))
{
lines.Add(
Expression.Assign(
Expression.Property(dataParam, "Value"),
Expression.Condition(
Expression.Equal(Expression.Property(parameters, prop.Name), Expression.Constant(null)),
Expression.Convert(Expression.Field(null, typeof(DBNull), "Value"), typeof(object)),
PropertyValueCastToObject(parameters, prop)
)
)
);
}
else
{
lines.Add(Expression.Assign(Expression.Property(dataParam, "Value"), PropertyValueCastToObject(parameters, prop)));
}
lines.Add(Expression.Call(Expression.Property(cmd, "Parameters"), typeof(DbParameterCollection).GetMethod("Add", new[] { typeof(object) }), dataParam));
}
var block = Expression.Block(new[] { dataParam, parameters }, lines);
return(Expression.Lambda <Action <DbCommand, object> >(block, cmd, obj).Compile());
}
static bool IsSupportedType(Type propertyType)
{
return(Types.IsStructured(propertyType) || Types.TypeToDbType.ContainsKey(propertyType) || propertyType.IsEnum || Types.IsNullableEnum(propertyType));
}